JPS58213090A - Method and device for removing hydrogen sulfide from crude coke oven gas - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for highly desulfurizing or removing hydrogen sulfide from crude coke oven gas by washing it with a recoverable aqueous cleaning liquid in a normal pressure system and a subsequent pressure system. and devices.

The coke oven gas produced when coking coal must be subjected to various refining processes before it can be used further for heating coke ovens, entering the city gas network or for other purposes. . In this case, the coke oven gas is usually desulfurized at low pressure, especially for reasons of corrosion and environmental protection. Such a cleaning method, together with its advantages and disadvantages, is described in "TJ], 1manns Enzy-1<1
Opadje der Technischen Ch.
emie”, Volume 10, 3rd edition, Mjnchen
]-958, pages 307 to 322, and illustrated. According to this, in general, in a coke factory, all the crude coke oven gas generated during coking is desulfurized by about 95% at normal pressure in a so-called wet process and is not required for specific operations, for example for heating the coke oven. Only the gas content is further desulfurized to the quality of city gas. This can be done by various "wet methods" working under pressure, i.e. using liquid cleaning agents, or by dry methods, for example using bog iron ore or bauxite smelting residues ("Ull'man").
ns Enzyklopadi.

der technj-schen Chemie”,
1958, Volume 10, Pages 307, 308, No. 3
14 pages). In this case, different methods with different detergents are used for prepurification under normal pressure and postpurification under elevated pressure. It is therefore a disadvantage that, in the case of cyclical methods, which are required for economic reasons, considerable costs are required for the after-treatment and recovery of the various cleaning agents. In terms of dry post-purification using swampite and similar materials, it is always difficult to use suitable adsorbent materials in sufficient quantities for the large gas volumes to be worked up. Furthermore, the method of recovering sulfur-enriched material and the method of obtaining sulfur from this recovery device is uneconomical.

The object of the invention is therefore to be able to purify all coke oven gases and to work exclusively with one category.
．． And almost no cost is required for recovery. The object of the present invention is to obtain a method for highly refining hydrogen sulfide from crude coke oven gas.

This problem is solved according to the invention by pre-washing the crude coke oven gas with the same washing liquid in an atmospheric system and post-washing in a pressure system, combining the sulfur-enriched washing liquid streams and using a common post-washing liquid. The solution is to treat, recover, and then distribute to atmospheric and pressure systems. According to the invention, a method of this type requires only one type of cleaning agent, and therefore the recovery is generally simplified and inexpensive accordingly. Surprisingly, the same cleaning agent can be used to work in different pressure systems without creating additional problems for recovery.

This method is therefore not only simple and inexpensive, but also particularly easy to understand.

According to an embodiment of the invention, the cleaning liquid is supplied from the pressure system to the atmospheric system for further enrichment, in whole or in part. In this case, the additional energy costs required are
Advantageously less can be kept, thus providing an additional advantage over the method according to the invention. A post-enrichment of the cleaning liquid from the pressure system is therefore immediately possible since the amount of sulfur still present in the gas in the pressure system is relatively small.

Another reduction in the sulfur content in the coke oven gas is achieved according to the invention by washing the coke oven gas with an alkali solution after leaving the pressure system. In this case, in particular caustic soda liquor is used, which is added after the washing step to destroy the ammonia compounds fixed in the coal water of the same or another coke plant.

The amount of caustic soda used is always the same or less than that required for the decomposition of fixed ammonia compounds in the coal water. The method used offers the significant advantage that a homogeneous and final desulphurization is always guaranteed.According to the invention, the coke oven gas is
2s 2 to 60 m9/Nm" and then post-cleaning with an alkaline wash. In this case, the hydrogen sulfide content is reduced before the alkaline step followed in coke oven gas. It is advantageous to have a constant adjustment.

Furthermore, an apparatus for removing hydrogen sulfide from crude coke oven gas by washing with a recoverable aqueous washing liquid in an atmospheric pressure system and a subsequent pressure system has a large number of washers, in which case: Atmospheric and pressure hydrogen sulfide scrubbers and caustic soda liquid processes are installed depending on the treatment method. The installation costs of this type of device are advantageously low and its monitoring and control is simplified. Preferably, ammonia water or an alkali-containing cleaning liquid is used as desulfurization medium for atmospheric and pressure systems. It is therefore also possible to use conventional desulfurization media which are present in sufficient quantities in coke plants.

The invention shows that a method is obtained which is easy to understand, easy to handle and monitor, which entails significantly reduced recovery costs, especially for the cleaning fluids used.

Example Coke oven gas 100,000 N771 at a coke factory
3/)] by wet desulfurization method to reduce H2S to about 0.5! 9/
Desulfurize to Nm3. 4500 ONrrLA is branched after low-pressure desulfurization for specific heating of the coke oven, and the remaining 5500ONm”/h is compressed to 6-12 pearls and then washed with the same cleaning solution as low-pressure desulfurization in another attached hydrogen sulfide scrubber. Highly desulfurized to almost H2S2m9/N'' using a split flow. It is also possible to desulfurize the total amount of coke oven gas.

The cleaning liquid streams from the low pressure system and the pressure system are worked up in a common recovery device and hydrogen sulfide is then obtained in the form of sulfur or sulfuric acid. By the way, in order to achieve the required reliable desulfurization of less than 2 m9 H2S/Nm'' in all operating conditions, the post-sulfur treatment is carried out either in the same column or in a subsequent column. The remaining hydrogen sulfide content is removed from the gas using caustic soda in a subsequent washing step.The enriched caustic soda is then added to decompose the ammonia compounds that fixate the coal water, in this case the sulfide The hydrogen is liberated and likewise treated to sulfur or sulfuric acid.As mentioned above, the amount of caustic soda is always equal to or less than the amount required to decompose the immobilized ammonia compounds in the coal water. It is a smaller amount.

It has likewise been found that it is also possible to use systems similar to caustic circulation cleaning or oxidative circulation cleaning in cleanings corresponding to other than aqueous ammonia and alkali-containing cleaning liquids as desulfurization media for atmospheric as well as pressure systems. Depending on the concentration and quality of the amount used on the pressure side of the desulfurization medium, the hydrogen sulfide content can be increased by H2S2 m before the subsequent caustic soda step.
9/Nm” and H2S about 60m9/Nm”. A low H2S content is necessary to ensure that the residual desulfurization required in the caustic soda process is achieved given the amount of caustic liquor to be used.

Sub-Agent: Patent Attorney Toshio Yano Continued from page 1 0 Inventor: Walter Koske, Dortmund, Federal Republic of Germany Intermediate Friedrich Hüpel Federal Republic of Germany Kastrup Laoxel Westerkampstrasse 29

Claims (1)

[Scope of Claims] 1. A method for removing hydrogen sulfide from crude coke oven gas by washing it with a recoverable aqueous cleaning liquid in a normal pressure system and a subsequent pressure system, in which the crude coke oven gas is washed with the same cleaning liquid. Pre-cleaning in the atmospheric system, post-cleaning in the pressure system, and combining the sulfur-enriched cleaning fluid streams, common after-treatment, recovery and subsequent distribution to the atmospheric and pressure systems. A method for removing hydrogen sulfide from crude coke oven gas, characterized by: 2. The method according to claim 1, wherein the cleaning liquid is fed from the pressure system, wholly or partially, to the atmospheric pressure system for further enrichment. 3. The method according to claim 1 or 2, wherein the coke oven gas is washed with an alkaline solution after leaving the pressure system. 4. 3-x furnace gas in a pressure system with H2S 2~60■
/Nm” and then post-cleaning with alkaline cleaning. 5. Recovering hydrogen sulfide from crude coke oven gas in an atmospheric pressure system and a post-contact pressure system. An apparatus for removing hydrogen sulfide by washing with a suitable aqueous cleaning solution, characterized in that hydrogen sulfide is removed from crude coke by washing with an aqueous cleaning solution, characterized in that atmospheric pressure system and pressure system hydrogen sulfide scrubbers and caustic sorter formation steps are incorporated depending on the treatment method. 6. Apparatus for removal from furnace gases. 6. Apparatus according to claim 5, in which aqueous ammonia or an alkali-containing cleaning liquid is used as desulfurization medium for atmospheric and pressure systems.